A. Field of the Invention
This invention relates to data processors, and more specifically to number processors. It particularly relates to the use of a specifically designed microprocessor device containing a stored microprogram for number processing tasks including arithmetic, trigonometric, logarithmic and other functions involving numeric data.
B. Description of Prior Art
Computers, calculators and microprocessors have long been used to process numeric data. In a typical application, software is written using the computer or microprocessor's unique instruction set to implement the complex mathematical routines required. Input/output routines are written to handle the entry, transfer and output of numeric data. Electronic calculator devices may be considered very specialized cases of the microprocessor device where the input/output routines and the hardware are optimized for use with keyswitch entry and display or numeric printer output.
In more sophisticated computers and mini-computers, hardware modules are sometimes added to perform certain arithmetic or special calculations. In this case, a typical system might implement a floating point add, subtract, multiply and divide capability using a multiplicity of integrated circuit logic elements. These hardware additions are usually specifically designed for a particular machine and tend to be quite expensive in comparison to other system hardware and their major function is to increase the operating speed of the arithmetic processing operations.
Since the cost of implementing even floating point arithmetic capability to a system is quite high with a strictly hardware approach, a more versatile and less costly system was needed. To be cost effective it was desirable that the system be compatible with a wide variety of systems, both stand-alone and computer or microprocessor controlled. It was also considered desirable that the number processing system be implemented on a single integrated circuit chip for economy and contain resident software library routines for control and for performing arithmetic, logarithmic and transcendental calculations on numeric data in floating point or scientific format.